A large number of pipe coupling arrangements have been proposed in the past. Among the most successful are the "Milne joint" (in which a washer is compressed until it bears against a pipe), the "barrel union" (in which an O-ring has pressure applied to it to seal the connection between the pipe ends), and the "slip-fix" coupling (which also relies upon the pressure applied to an O-ring to establish the seal between the coupled pipe ends). Other proposals which have not been successful (in that they are not available on the Australian market) are featured in the specifications of UK patent No. 1,357,412, UK patent application No. 8415399 (publication No. GB-2166825A, the invention of which was conceived primarily for connecting the ends of hoses), U.S. Pat. No. 4,095,826, U.S. Pat. No. 3,667,782 and U.S. Pat. No. 4,548,428.
All of these prior art connectors are either incapable of withstanding high pressures, or are very expensive to produce and thus are not economically viable connectors. Few of these pipe connection arrangements could be used to join the ends of a broken pipe when the pipe which has fractured is fixed in position (for example, by being buried underground) and there is no prospect of axial movement of the two lengths of pipe.